7B30.23 - Franck - Hertz : Critical Potential Tube

See procedure.
See procedure.
Code Number:
Demo Title:
Franck - Hertz : Critical Potential Tube
Critical Potential in a Gas
Area of Study:
Modern Physics
Franck - Hertz Xenon Tube Unit, 0 to 20 VDC Power Supply, 2 - Variacs, 2 - 6 volt Transformers, Volt and Amp Meters, Oscilloscope.

By carefully varying the voltage on the 0 - 150 VDC power supply three different peaks corresponding to three different energies of helium may be shown at one time. It will take several minutes for the dry cell to stabilize to an amperage output of about .1 to .2 amps. The amperage may be as high as 4 to 5 amps when the dry cell is first connected. An amp meter should be used to monitor this condition. NOTE: MAKE SURE ALL THE POWER SUPPLIES ARE AT MINIMUM OUTPUT BEFORE THEY ARE HOOKED TO THE TUBE AND TURNED ON. THIS WILL INSURE THAT THE TUBE REMAINS UNDAMAGED!! Note that the oscilloscope hookup that works best for our situation is a little different than the diagram that comes with the tube instruction.  

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